[Serum sex hormone-binding globulin levels in thyroid diseases]

Synthesis of "sex-hormone binding globulin" is influenced by the thyroid hormones and its concentration in the serum may be a marker of the thyroid hormone effect at the peripheral tissue (liver) level. Compared to euthyroid controls serum "sex-hormone binding globulin" concentration is elevated in overt hyperthyroidism (141.6 +/- 37.6 vs 48.3 +/- 16.2 nmol/l; p less than 0.001), conversely, its mean level is decreased in the hypothyroid group of patients (24.9 +/- 14.8 vs 48.3 +/- 16.2; p less than 0.001). In the group of subclinical hyperthyroidism the mean value of "sex-hormone binding globulin" corresponds to that in control subjects (47.4 +/- 16.8), while its serum level is near the lower border of the normal range in subclinical hypothyroidism (33.6 +/- 6.1 vs 48.3 +/- 16.2; p less than 0.01). During thyroid hormone replacement for hypothyroidism measurement of serum "sex-hormone binding globulin" may help to assess the response of the target organs to the hormone therapy. In patients with peripheral thyroid hormone resistance serum "sex-hormone binding globulin" level is within the normal range (51.3 +/- 9.8), its determination supports the diagnosis of this disease.